This is a simple Swiss side dish. Do not forget to cook the potatoes at least a day beforehand. Do not stir the Roesti because it will be prevented from forming its crust. Add finely chopped, lean bacon, sliced onions, or thinly sliced cheese for other variations.
Place the potatoes in a large pot. Cover the potatoes with water. Bring the water to a boil over medium-high heat. Cook the potatoes until tender enough to pierce with a fork, about 15 minutes; drain and refrigerate potatoes overnight.
Peel and grate the potatoes into a large bowl.
Melt the butter in a skillet over medium heat; add the grated potatoes; season with salt. Press the potatoes into a round loaf using a spatula. Sprinkle the milk over them. Cover the skillet with a lid. When you hear the potatoes begin to sizzle in about 5 to 10 minutes, reduce the heat to low. Cook until a brown crust has formed on the bottom, about 30 minutes. Cover the skillet with a large plate and flip the roesti onto the plate to serve.
Per Serving: 186 calories; protein 3.1g; carbohydrates 31.1g; fat 5.9g; cholesterol 15.5mg; sodium 436.1mg.